Voltage reducing device for welding transformers



c. P. SONIUS 2,668,273

VOLTAGE REDUCINGDEVICE FOR WELDING TRANSFORMERS Feb. 2, 1954 Filed Sept.13, 1950 INVENTOR. Cor-we 2w P Ja /v. us

Patented Feb. 2, 1954 x n viberoaiwemmo-i raens aneas Gomelisi PieteaSonius, Gron-ingen; Netherlands,

assign: tpliennootschap. onden firma' Oscars;

Kain. Gmonins ni flet anda fitQQEDQiIMiQQfl-ll? thehietlies aedsi v.1natal sheets 13. lihtfieria ies (Elaine priority; application Nether andc Sep ember 22, 1949 This invention he to; avoliaee; eal sing th w d ng;vo tage wh h during he eld a device more particularly forwelding trahsformprocess will act continuously n; the relay is by wi ii hithe eleaie il age Qt s derab hig er, "thi drawbaokflis yennmore,

A 1 g? which, gu rantees se ous-L en st e e irode and. e urn in si' q onn W ding b s; a l i w ich quire eh oltaeea. are us d,

t h sati y le es, t a swer; ts urpose). he. vo tage in the eriod ha n wdin s be n do e. lllhewe e edups to. r iqw .2 o s, so, ha he ela w th ao ta e; coi ust spo a ec ndary volt ge below 4. volts; w v

On c o e use on w ldin cables. which will cause a considerable loss of,voltage d; the mo rn; i st el; lectro es nd; dee b r in I-Qdfifin he sndam Jm QS Q1 he l rans ormer aresons derabw h her an. l s! so: that onsru tions com r sin a voltage coilj are unsuitable formodern weldingtransformers,

According o. he v nt oaa o a e reducin device for a. w ldin transform rWherem.- b a firfenfl r, A means of, arelay connected in theisecondaryairof windin s. c, Quit o th nsfor r, r -h ts wilin ertedI i itenhe perao iof. hei voltage he im ra imuitis ids q m ris .nea e aa reducing chokecoil" has onc'e'been bridged, the l lalvir g a; current coil connectedin. series with ansimn et mediarima w e l iaq ile i he se on a y. ircuiand a. vol age c. 11 con to thfull'voltage" of the mainsand on thesecnected in, parallel. with the secondary, wi g ondary windingthefull-power is available so that oi thetransfp im lfg her l x QhtaQW-DQlgpQen, the welding current will increase to a maximum only whenthevoltage; co l, isenergized andbe va ue.' v n lo d nh re v si one helay Dunne-the weldin o eratiom ela eby he t n. of the ini ures weightser iz d hde oth e nfluens of t e weldand/0: X- pr naac ina n, d a mture. an ing current, the intensityof, which. is many times in theenergized conditioner currentcqil, higher than that of the firstrush ofcurrent, 'Ijhe inventio nwill now lee described llo i fi a" so thatowing to this high" intensity of the we1d--v erence totheaccornpanyingdrawing, which 11;- ing cur-rent: 'andthegreatnumber of windings,lustrates a, p ieierred embodiment of a circuit the magnetic fluxthrough the iron of the relay @lflfingement in; 1611% elay ogoljdihg the may increase to such a value as to create a invention is used.supersaturation owing to which the iron is greatly 40 he Welditransformer I has its p m y heated and becomes burned. winding 2connected to the terminals II and 12 The object of this invention is toobviate this of the feeding mains via a voltage reducing choke drawbackby avoiding a super-saturation of the coil 4. The ends of the choke coil4 are coniron of the voltage reducing relay. nected with the contacts ofa relay 6 and are It is also known to energize the relayconshort-circuited by a bridge-contact 5 in the necting the voltagereducing choke coil in the operative condition of the relay 6. primarywinding of the welding transformer, Furthermore, the welding transformerhas its instead of by the welding current in the secondsecondary windin3 Connected With a vol a ary Winding of the welding transformer, bymeans coil 9 of a relay I0, which voltage coil is conof the influence ofthe welding voltage. In this nected in parallel with said secondarywinding 3 case the relay is provided with a voltage coil, in- The saidvoltage coil consists of a relatively stead of a current coil. largenumber of windings of insulated thin cop- The use of a voltage coil onlyhas the drawper wire. The relay [0 comprises also a current back thatthe relay must respond already to a coil 8 of a relatively small numberof windings of voltage that is harmless to the welder, whereas insulatedthick copper wire. The current can 8 is connected in series with thewelding circuit which is closed via the terminals 13 and I l. The twocoils 8 and 9 act on the armature of the relay III. In the non-energizedcondition of the coils 8 and 9 the contacts I of the relay ID are closedbecause the armature under the influence of its own weight or under theaction of a spring is in the inoperative condition. Furthermore therelay It] is constructed so that if only the voltage coil 9 is energizedthe armature is drawn out of the :1:

inoperative condition and the contacts 7 are opened. If only the currentcoil 8 is energized, the contacts I are closed and if in addition thevoltage coil 9 is subsequently energized, this coil is not able to movethe armature in opposition to the action of gravity and/or of the springand in opposition to the action of the current coil, to open thecontacts 1.

The coil of the relay 6 is energized by the current from the mains viathe contacts 1.

Before the welding apparatus is connected to the feeding mains H, I2 thetwo relays 6 and H) are in the inoperative condition, the bridge contact5 is open and the contacts I are closed.

When the welding apparatus is connected to the feeding mains, thevoltage coil 9 of the relay H3 will be energized by the current from thesecondary winding 3 of the welding transformer 1 whereby the armature ofthis relay will operate and open the contact l, so that the relay 6continues unenergized and the voltage-reducing choke coil 4 is includedin the primary circuit of the welding transformer, while the secondaryvoltage has a value which guarantees safety to the welder.

When subsequently the welding operation is initiated by contacting thewelding electrode with the work-piece, the terminals i3 and M are shortcircuited thereby so that the secondary voltage will drop sharply andthe energization of the voltage coil 9 will be discontinued, as a resultof which the armature of the relay It! will be released and the contacts1 will be closed. The relay 6 via said contacts is now energized by thecurrent from the feeding mains, so that the bridge-contact 5 will nowshort-circuit the volt-' age reducing coil 4, as a result of which thefull voltage of the mains will be applied to the primary winding of thewelding transformer and the full power will become available at the sec-D and the armature of the relay H1 is only attracted by the energizationof the voltage coil 9 as a result of which the contact I will open andthe relay 5 will become inoperative, so that the voltage-reducing chokecoil .is'cut in and the secondary voltage will again drop to a safevalue.

Since according to the present invention the current coil 8 only has toprevent the armature of the relay [0' from being attracted by thevoltage coil 9, wherein said current coil is assisted by the action ofgravity and/or the action of a spring on the armature, said coil 8 maybe provided with a small number of windings only, so thatnotwithstanding the high intensity of the welding current passingthrough this coil the possibility of the iron being burnt is excluded.Also in view of the manufacture of the current coil in which manufacturea thick wire capable of carrying the maximum welding current has to beused, a small number of windings constitutes an advantage over thecurrent coil, or the voltage coil, of the known devices.

I claim:

A voltage reducing device for welding transformers having a primarywinding and a sec ondary winding, a primary circuit including saidprimary winding, a secondary circuit including said secondary winding,comprising a choke coil connected in the primary circuit, a contactorfor short circuiting the choke coil, a relay for actuating the contactorincluding an actuating armature having a tendency to move to contactclosing position, a voltage coil connected in parallel with thesecondary winding of the transformer and positioned to magnetically movethe actuating armature to contact opening position upon the applicationof the voltage of the secondary winding thereto, and a current coilconnected in the secondary circuit in series with the secondary windingof the transformer and positioned to magnetically overcome the magneticeffect of the voltage winding and shift the actuating armature tocontact closing position upon the flow of current from the secondarywinding through the current winding.

CORNELIS PIE'IER SONIUS.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,343,203 Eschholz June 15, 1920 1,343,204 Eschholz June 15,1920 1,343,205 Eschholz June 15, 1920 FOREIGN PATENTS Number CountryDate 143,4 Switzerland Nov. 15, 1930

